[1] Univ Cambridge, Inst Metab Sci, Sch Clin Med, MRC Epidemiol Unit, Cambridge, England
[2] London Sch Hyg & Trop Med, Fac Publ Hlth & Policy, Dept Publ Hlth, Populat Hlth Innovat Lab, London WC1H 9SH, England
[3] Great Ormond St Inst Child Hlth, 30 Guilford St, London, England
[4] London Sch Hyg & Trop Med, Clin Res Dept, London, England
[5] Queen Mary Univ London, Wolfson Inst Populat Hlth, Barts & London Sch Med & Dent, London, England
[6] Univ Melbourne, Sch Populat & Global Hlth, Allergy & Lung Hlth Unit, Melbourne, Vic, Australia
[7] Univ Edinburgh, Usher Inst, Asthma UK Ctr Appl Res, Edinburgh, Scotland
[8] Univ Oxford, Nuffield Dept Primary Care Hlth Sci, Oxford, England